hello everyone and new to the forum hope I can find some answers and abit of help :)

my mate has been playing mario kart online for about a year now and hes been upgrading his wii and everything was fine until TODAY he updated to a new version which is 4.2u . the problem he bought the wii already modchipped and he doesnt know whats the chip is there any way to find out whats the right one?

my other question is , if he does deletes everything from the wii could it be a solution for this or is there another way to do it like going back a version?